Monocyte-macrophage modulation of T-lymphocyte-derived colony-stimulating activity elaboration in man

To investigate the source and the mechanisms of synergistically enhanced colony-stimulating activity elaboration by the coincubated monocyte-macrophages and T lymphocytes, we simultaneously prepared conditioned media both from the coincubated monocyte-macrophages and T lymphocytes (ratio 1:3) in the presence of phytohemagglutinin (1%) or methanol extraction residue of bacillus Calmette-Guerin (50 micrograms/ml) and from the isolated T lymphocytes that had been primed with monocyte-macrophages in the presence or absence of phytohemagglutinin or methanol extraction residue of bacillus Calmette-Guerin. Subsequently, colony-simulating activity in various conditioned media was assayed using light-density (less than 1.070 g/ml), nonadherent normal human marrow cells. Live monocyte-macrophages synergized with and significantly (P less than 0.01) agumented the T lymphocyte-derived colony-stimulating activity elaboration; while killed monocytes-macrophages had no such effect. Similarly, actinomycin D and cycloheximide not only diminished monocyte-macrophage colony-stimulating activity elaboration but also reduced their synergistic interaction with T lymphocytes and their ability to augment the T lymphocyte-derived colony-stimulating activity elaboration. In contrast, mitomycin C failed to diminish both - monocyte-macrophages' ability to synergise with T lymphocytes and also to augment T lymphocyte-derived colony-stimulating activity. These data suggest that monocyte-macrophages require an intact transcriptional and translational processes, but not DNA synthesis for synergising with T lymphocytes or for augmenting T lymphocyte colony-stimulating activity elaboration.